Over the course of a typical day, cafeterias generally use, wash and re-use a large number of dishes, e.g., plates, cups, and glasses on a continuous basis. A series of manually portable dishware trays, each providing a number of top opening compartments sized to receive one or more pieces of dishware, is often used by the cafeteria to facilitate dispensing of the dishes to retail customers. The trays are usually sized and structured to be stacked vertically one on top the other in the cafeteria line.
Dishware dispensers are well known to the prior art. A dishware dispenser supports a number of stacked dishware trays upon a rack within a box-like, mobile frame. When the supply of dishes, e.g., glasses, in the top tray is exhausted, the top tray is removed to provide access to glasses in the tray immediately below. Subsequent exhaustion of glasses in the tray just below requires removal of that tray, and so on. Eventually, this results in an empty dishware dispenser, whereupon another stack of trays containing clean dishes is placed upon the rack.
Self leveling dishware dispensers are known which provide a rack that is vertically movable with respect to the frame. The rack, in commercial embodiments of which we are aware, is spring biased upwardly to maintain the top dish tray in the stack at a relatively constant height regardless of the number of trays in the stack. As the weight of the stack decreases, i.e., as dishes and trays are removed, a spring mechanism forces the rack upward until a new equilibrium is reached between tray weight and spring force. Theoretically, this should place the top tray at the desired height for use by the customer.
A significant inherent problem exists in maintaining the proper dispensing height of a self leveling dishware dispenser of the spring elevated type. This problem occurs as a result of improperly filled trays, partially filled trays, and changing weights and sizes of dishware items to be dispensed. So designers, contractors and suppliers must continuously verify the sizes and weights of the items to be dispensed in order to properly size the dishware dispenser's spring mechanism. In other words, the performance of such prior art dishware dispensers depends upon proper initial spring calibration, and reliable adjustment mechanisms, which allow spring adjustment after the dispenser has been in use for a period of time. Otherwise, the dispenser will not be properly responsive to the trays from which dishware is to be dispensed.
Accordingly, it is the objective of this invention to provide an improved self-leveling dispenser which overcomes the disadvantages associated with dishware dispensers of the spring mechanism type.